RAC Startup sequence Short

The Oracle RAC 11gR2 startup sequence is below as:

1.      The OLR service is started.

2.       The ohasd process starts and accesss the OLR service and complete its initialization. It then spawns:

1.       its orarootagent process.

2.       its oraagent process.

3.       cssdagent process.

4.      cssdmonitor process.

3.       ohasd orarootagent process spawns the gpnpd process and cssdagent process spawns the cssd process. The cssd daemon then access the local GPNP profile of the node to get the disk locations of all the voting disk files and complete its reconfiguration with the cluster.

4.       The ctssd daemon and diskmon process are then started by ohasd orarootagent process. The diskmon process checks the ADVM/ACFS devices.

5.       The ohasd oraroot agent then starts the crsd process. The crsd process check the OCR data by starting the OCR service and complete its initialization.

6.       The evmd process is then started by oraagent process.

7.       The crsd process spawns its oraagent and orarootagent process. These two crsd processes then parellely spawns their further processes coordination:

the CRSD orarootagent then further spawns the below resources:

1.      Network resource : for the public network

2.      SCAN VIPs

3.      Node VIPs : VIPs for each node

4.      ACFS Registry

5.      GNS VIP : VIP for GNS if you use the GNS option

and the CRSD oraagent spawns the below resources:

1.      ASM Resources  

2.      Diskgroups

3.      DB Resources

4.      SCAN Listener : Listener for SCAN listening on SCAN VIP

5.      Listener : Node Listener listening on the Node VIP

6.      Services : Database Services

7.      ONS

8.      GSD

9.      GNS

Thanks & Regards

Nikhil Kumar.